ESTRO 2025 - Abstract Book

S4073

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2025

Spatial Direction

R

P

＜ 0.01

Lateral

0.834

＜ 0.01

Longitudinal

0.960

＜ 0.01

Vertical

0.972

＜ 0.01

Pitch

0.968

＜ 0.01

Roll

0.961

＜ 0.01

Yaw

0.934

Conclusion: SGRT with customized polyurethane foam casting is proven to be a reliable solution for pediatric radiation therapy. It not only provides treatment accuracy, but also elevated the patient comfort and ensure patient safety throughout the treatment.

Keywords: pediatrics radiation therapy,SGRT

1900

Proffered Paper Preliminary comparison of CT simulation free workflows for MSCC patients on an MR Linac Alice Greenwood-Wilson 1 , Frank Brewster 2 , Lisa McDaid 1 , Benedict Dobby 1 , Robert Chuter 2,3 , Peter J Hoskin 3 , Cynthia L Eccles 1,3 1 Radiotherapy, The Christie NHS Foundation Trust, Manchester, United Kingdom. 2 Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, United Kingdom. 3 Division of Cancer Sciences, Faculty of Medicine, Biology and Health, The University of Manchester, Manchester, United Kingdom Purpose/Objective: The MR Linac may facilitate rapid treatment for patients with metastatic spinal cord compression (MSCC) using a “scan, plan, treat” single session model. This work assessed the feasibility of a simulation-free MR-based online workflow and compared its time efficiency to an offline diagnostic CT (dCT) workflow (1), to determine the most efficient prior to clinical implementation. Material/Methods: Two proposed workflows for CT-simulation free MSCC treatment on a 1.5T MR Linac were tested using the Monaco planning system (V5.51.11, Elekta). The current departmental protocol of 8Gy in one fraction delivered using a single posterior beam was used. The offline workflow used a recent dCT to create a reference plan to be registered and adapted to an on-treatment T1 MRI. For the online workflow, a T1 MRI acquired on the MR Linac was used to create a treatment plan whilst the patient was on the treatment couch. For both workflows a clinical target volume (CTV) was defined as the area of compression plus one vertebra above and below and 8Gy was prescribed to the anterior spinal cord. Three participants were recruited onto the PRIMER imaging study (NCT02973828), 1 with and 2 without vertebral pathology. All participants were scanned and planned over 1-2 appointments using both workflows (Figure 1). Timed tasks included participant setup, image registration, treatment planning and/or adaptation with plan export as the end point. The total time to complete all tasks for both workflows was also compared.